Custom Malloc Implementation

Malloc's Heap (Tiny and Small zones)

Run tests

Linux

make re && gcc -g tests/test_complex.c -o test -L. -lft_malloc -Wl,-rpath=. && ./test

Mac

make re && gcc -g tests/test_complex.c -o test -L. -lft_malloc && ./test

Used functions

1. mmap - request memory from os
2. munmap - return memory to os

Features

1. Coalescing
2. Arenas for small and tiny allocations
3. Explicit free list for O(free blocks) search time

The memory translation process

VIRTUAL MEMORY -> PHYSICAL MEMORY

• TLB Lookup - TLB is a cache that stores recent mappings between virtual addresses and physical addresses. When a virtual address needs translation, the MMU(Memory Mgmt Unit) first checks TLB.

• TLB Hit: If the mapping is found in the TLB, the physical address is returned.

• TLB Miss: If the mapping is not found in the TLB, the MMU performs a page walk to look up the mapping in the page table.

  • Page Table Results
    • Mapping exists: The MMU writes the mapping into the TLB so that future translations result in a TLB Hit.
    • Mapping does not exist: A page fault occurs. If address is invalid segmentation fault is triggered. If address is not loaded in RAM, it is stored on disk. OS retrieves the data from disk and updates page table.

Materials

• CS361: Systems Programming, University Of Illinois Chicago